1. Field of the Invention
This invention relates generally to the fluid conditioning art and more particularly to an improved fluid conditioning device for conditioning a fluid by filtering matter from the fluid, adding matter to the fluid, or both removing matter from and adding other matter to the fluid.
2. Prior Art
According to its broader aspects, this invention is concerned with fluid conditioning devices of the class characterized by a housing having a fluid inlet and outlet, a fluid passage communicating the inlet and outlet, and a fluid conditioner within the passage through which fluid flows from the inlet to the outlet. The fluid conditioner may be designed to condition the fluid by adding matter, such as a treatment chemical, to the fluid, removing matter, such as contaminants, from the fluid, or both adding matter to and removing matter from the fluid. For example, one type of fluid conditioning device of the class described is a filter which removes solids from a fluid. Another type of fluid conditioning device is a reverse osmosis device that separates a molecular constituent from a solution, such as the saline constituent from sea water. Yet another type of fluid conditioning device adds a substance to the fluid.
This invention is primarily concerned with fluid conditioning devices of the first two types just mentioned, that is, solid matter filtering devices and reverse osmosis devices, and will be described mostly in this context. For convenience, these conditioning devices are referred to herein generically in places as fluid filtering devices or simply filters. It will become evident as the description proceeds, however, that the invention contemplates within its scope a fluid conditioning device which adds matter to a fluid instead of or in addition to removing matter from the fluid.
The fluid filtering art is very highly developed and replete with a vast assortment of fluid filters for a wide variety of filtering purposes. Among the patents in this field are the following: U.S. Pat. Nos. 4,402,828, 4,253,959, 4,388,191, 3,771,664, 4,966,697, 4,935,128, 4,157,964, 5,006,243, 4,986,912, 4,664,798, 4,204,966, 4,133,769, 4,021,354, 3,675,776. Of these patents, the first two listed are believed to be the most pertinent to this invention.
One of the major problems involved in the design, fabrication, and use of fluid conditioning devices of the class described is sealing the internal fluid conditioner to the housing to prevent passage or leakage of unconditioned fluid between the conditioner and the housing. This problem is particularly troublesome in fluid conditioning devices having fluid conditioners which are removable for servicing or replacement and those conditioning devices which handle high pressure fluid. While a wide variety of sealing arrangements have been devised for this purpose, none are totally satisfactory, especially for use in high pressure filtering devices having removable internal filter units.